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CHEMISTRYCHEMISTRY

MID TERM EXAM REVIEWMID TERM EXAM REVIEW

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1. How many atoms of hydrogen are present in 3 moles of acetic acid?

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1. How many atoms of hydrogen are present in 3 moles of acetic acid?

3 mol Ac x 4 moles H x 6.02 X 1023atoms H 1 mole Ac 1 mole H

= 7.22 X 1024atoms

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2. What is the molecular formula of butane?

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2. What is the molecular formula of butane?

C4H10

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3. How many moles of carbon are present in 2 moles of butane?

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3. How many moles of carbon is present in 2 moles of butane?

2 mol butane x 4 mol C = 8 mol C 1 mol butane

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4. What is the percent composition of ethanol?

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4. What is the percent composition of ethanol?First find MOLAR MASS2C = 2 x 12.0 = 24.06H = 6 x 1.0 = 6.01O = 1 x 16.0 = 16.0Total 46.0 g/mol

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4. - continued What is the percent composition of ethanol?

Mass of each element / Total x 100 = %

%C = 24.0/46.0 x (100) = 52% %H = 6.0/46.0 x (100) = 13%%O = 16.0/46.0 x (100) = 35%

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5. Classify the reactions shown below

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5.Classify the reactions shown below

Decomposition

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5. Classify the reactions shown below

Decomposition

Double replacement

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5. Classify the reactions shown below

Decomposition

Double replacement

Synthesis

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5. Classify the reactions shown below

Decomposition

Single replacement

Synthesis

Double replacement

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6. What number should be written in front of Na to balance the

equationNa + Cl2 NaCl ?

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6. What number should be written in front of Na to balance

the equationNa + Cl2 NaCl ?

22Na + Cl2 2NaCl

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7. What number should be written in front of Fe in order to

balanceFe + O2 Fe2O3?

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7. What number should be written in front of Fe in order to

balanceFe + O2 Fe2O3?

4

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7. What number should be written in front of Fe in order to

balanceFe + O2 Fe2O3?

4 4Fe + 3O2 2Fe2O3

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8.Measure the object with the ruler to the correct number of

significant figures.

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8. Measure the object with the ruler to the correct number of significant figures. 11.65 cm

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8. Measure the object with the ruler to the correct number of significant figures. 11.65 cm

Must make ONE estimate smaller than marks.

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9. Classify each as accurate &/ or precise

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9. Classify each as accurate &/ or precise

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10. What symbol expresses uncertainty in a measurement?

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10. What symbol expresses uncertainty in a measurement?

+/-

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11. Name the compound S3O6

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11. Name the compound S3O6

Trisulfur hexoxide

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12. What is the formula for the compound that is formed by magnesium and hydroxide ions?

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12. What is the formula for the compound that is formed by magnesium and hydroxide ions?

Mg(OH)2

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13. What is the formula for the compound that will form between calcium and phosphate ions?

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13. What is the formula for the compound that will form between calcium and phosphate ions?

Ca3(PO4)2

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14. What is the correct formula for barium oxide?

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14. What is the correct formula for barium oxide?

BaO

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15. What is the volume of a mole of gas at STP?

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15. What is the volume of a mole of gas at STP?

22.4 L

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16. In a chemical reaction, the total mass of the products compared to the total mass of the reactants is

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16. In a chemical reaction, the total mass of the products compared to the total mass of the reactants is

always the same

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17. Calculate the number of atoms in 1.40 mol of Ag.

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17. Calculate the number of atoms in 1.40 mol of Ag.

1.40 mol x 6.02 X 10 23 atoms

1 mol

= 8.43 X 10 23 atoms

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18. Calculate the number of liters of gas in 1.47 mols at STP

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18. Calculate the number of liters of gas in 1.47 mols at STP

1.47 mol x 22.4 L

1 mol

= 32.9 L

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19. In the formula Ca3(PO4)2, the total number of oxygen atoms is

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19. In the formula Ca3(PO4)2, the total number of oxygen atoms is

2 X 4 = 8 oxygen atoms

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20. In the formula 3 Mg(NO3)2, the total number of oxygen atoms is

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20. In the formula 3 Mg(NO3)2, the total number of oxygen atoms is

3 (3 X 2) = 18 oxygen atoms

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21. In the formula 3 Mg(NO3)2, the total number of atoms is

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21. In the formula 3 Mg(NO3)2, the total number of atoms is

18 oxygen atoms +

3 Mg atoms +

6 nitrogen atoms

= 27 total atoms

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22. In the expression 3Mg(NO3)2, the number 2 is known as the ______.

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22. In the expression 3Mg(NO3)2, the number 2 is known as the ______.

subscript

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23. In the expression 6 Ca3(PO4)2, the 6 is known as the _____.

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23. In the expression 6 Ca3(PO4)2, the 6 is known as the _____.

coefficient

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24. What is the name of the Law that directs us to balance equations?

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24. What is the name of the Law that directs us to balance equations?

The Law of

Conservation of Matter

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25. When oxygen is available, nitrogen dioxide is produced from the burning of nitrogen. Write the word equation for this reaction.

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25. When oxygen is available, nitrogen dioxide is produced from the burning of nitrogen. Write the word equation for this reaction.

nitrogen + oxygen nitrogen dioxide

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25. When oxygen is available, nitrogen dioxide is produced from the burning of nitrogen. Write the word equation for this reaction.

oxygen + nitrogen nitrogen dioxide

also acceptable

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26. Give two examples of a chemical change.

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26. Give two examples of a chemical change.

Souring milk, burning anything, cooking, rotting, decaying leaves, releasing a gas, reacting to…

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27. Classify each of the following reactions:

2 Mg + O2 MgO

CH4 + O2 CO2 + 2 H2O

AgNO3 + NaCl NaNO3 + AgCl

H2O H2 + O2

AgCl + Cu CuCl + Ag

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27. Classify each of the following reactions:

2 Mg + O2 MgO synthesis

CH4 + O2 CO2 + 2 H2O combustion

AgNO3 + NaCl NaNO3 + AgCl double replacement

H2O H2 + O2 decomposition

AgCl + Cu CuCl + Ag single replacement

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28. Balance each of the following equations

a. NaCl Na + Cl2

b. S + Cl2 SCl3

c. K + AgCl Ag + KCl

d. Ca(OH)2 + HCl H2O + CaCl2

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28. Balance each of the following equations

a. 2 NaCl 2 Na + Cl2

b. 2 S + 3 Cl2 2 SCl3

c. K + AgCl Ag + KCl

d. Ca(OH)2 + 2 HCl 2 H2O + CaCl2

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29. Use the experiment shown in the figure to answer the questions

a. A gas was given off, collected in a test tube, and then tested with a burning splint. A “pop/chirp” was heard. What was the gas?

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29. Use the experiment shown in the figure to answer the questions

a. A gas was given off, collected in a test tube, and then tested with a burning splint. A “pop/chirp” was heard. What was the gas?

What are the reactants?

What type/classification of reaction?

What are products?

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29. Use the experiment shown in the figure to answer the questions

a. A gas was given off, collected in a test tube, and then tested with a burning splint. A “pop/chirp” was heard. What was the gas?

Mg + HNO3

single replacement

hydrogen + magnesium nitrate

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29. Use the experiment shown in the figure to answer the questions

a. A gas was given off, collected in a test tube, and then tested with a burning splint. A “pop/chirp” was heard. What was the gas?

hydrogen NOT the magnesium nitrate

ionic compounds are solids or dissolved (aq) in water

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29. Use the experiment shown in the figure to answer the questions

b. The substances Mg metal and dilute HNO3, are called --?

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29. Use the experiment shown in the figure to answer the questions

b. The substances Mg metal and dilute HNO3, are called --?

reactants

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29. Use the experiment shown in the figure to answer the questions

c. Write the correct balanced equation for the experiment

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29. Use the experiment shown in the figure to answer the questions

c. Write the correct balanced equation for the experiment

Mg + 2HNO3 H2 + Mg(NO3)2

diatomic ionic : charges